This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from my application entitled THE FIXING ROLLER POWER-SOURCE SUPPLY APPARATUS OF ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS filed with the Korean Industrial Property Office on May 4, 2001 and there duly assigned Serial No. 2001-24379.
1. Field of the Invention
The present-invention-relates to a fusing roller having an electrical connection between a heater hermetically sealed within the fusing roller and an external power supply, the fusing roller being used in an electrophotographic image formation apparatus, and more particularly, to a fusing roller having an electrical connection between a heater hermetically sealed within the fusing roller and an external power supply, the electrical connection providing an improved structure for securing durability and safety in an electrophotographic image formation apparatus.
2. Description of the Related Art
Generally, electrophotographic image formation apparatuses such as copiers and laser printers using an electrophotographic development method uniformly charge a photosensitive body formed on the outer surface of a photoreceptor drum by rotating an electrostatic charging roller adjacent to the photoreceptor drum. The photosensitive body is exposed to a laser beam emitted from a laser scanning unit (LSU) in a predetermined pattern so that a desired electrostatic latent image is formed on the surface of the photosensitive body. A developer supplies a toner to the photosensitive body, thereby developing the electrostatic latent image formed on the photosensitive body into a visible image, i.e., a toner image in powder. Thereafter, a predetermined transferring voltage is applied to a transferring roller contacting the photoreceptor drum at a predetermined pressure and to the photoreceptor drum on which the toner image is formed. In this state, when a sheet, i.e., a recording medium, passes through the gap between the photoreceptor drum and the transferring roller, the toner image is transferred to the sheet. A fixing unit including a fusing roller heats the sheet to which the toner image is transferred in order to temporarily fuse the toner image in power state to be stuck to the sheet. Radiant heat generated from a heating source of the fixing unit heats the surface of the fusing roller to a predetermined temperature. The heating source is supplied with power from an external power supply and generates radiant heat. The heating source is connected to the external power supply through an electrical connection between the heater and the external power supply, thereby being supplied with current.
It is generally desirable to have the heating unit located on an inside of a cylindrical fusing roller and have the heating unit hermetically sealed from exterior elements because the heating unit and the fusing roller undergo sudden electrical and thermal changes versus time. If the heating unit were exterior to the fusing roller, a safety hazard would be present as a result of the power surges, and the mechanical durability of the device would be sacrificed. What is needed is a design for delivering power to the hermetically sealed heater inside the fusing roller without compromising the hermetic seal, the safety of the device, and without compromising the mechanical durability of the fusing roller unit.
It is therefore an object to provide an improved fusing roller used in an electrophotographic apparatus.
It is also an object to provide a fusing roller where the heating unit is located inside the fusing roller and the heating unit extends the entire length of the fusing roller.
It is further an object to hermetically seal the interior of the fusing roller having the heating element to prevent exposure of the heating element from the atmosphere and to prevent any working fluid or substance initially introduced to the interior of the fusing roller not to leak out or degrade.
It is further an object to provide an electrical connection between the heating element hermetically located within the fusing roller to a power supply located exterior to the fusing roller without compromising on the quality of the hermetic seal, on the safety of the device and on the mechanical durability of the fusing roller unit even when the external power supply applies large power surges to the heater stored within the fusing roller used in an electrophotographic image formation apparatus.
Accordingly, to achieve the above objects of the invention, in one embodiment, there is provided a fusing roller with an electrical connection between the heater and the external power supply for electrically connecting an external power supply to a heater in an electrophotographic image formation apparatus. The fusing roller having the electrical connection between the heater and the external power supply is installed at both ends of a fusing roller and includes a pipe-shaped cap and a slip ring. The cap is formed of a nonconductive material and provided with a hole through which a lead of the heater can pass at one side. The slip ring is installed about the cap and a coupler electrically contacting the lead (or end) of the heater.
In other embodiments, there is provided a fusing roller with an electrical connection between the heater and an external power supply of an electrophotographic image formation apparatus. The electrical connection between the heater and the external power supply includes a pipe-shaped coupling cap and a slip ring. The coupling cap is non-conductive and is connected to a conductive cap of a heater at one end and to a conductive slip ring at the other end. The coupling cap is provided with a via-hole through which a lead of the heater passes through. The slip ring is installed at one end of the coupling cap and transmits current supplied from an external power supply to the heater.